Gripping face for chucks and method of making the same



March 14, 1933. L, R: EVANS 1,900,922

GRIPPING FACE FOR GHUCKS AND' METHOD OF KAKING= THE SAME` Filed Sept. 23. 1930 Patented Mar. 14, 1933 UNITED STATES PATENT OFFICE LmGH B. EVANS, OF MIRA, NEW YORK, ASSIGNOB TO MORRISON IACHINE PBODUUIB, INO., OII` ELIIBA, NEW YORK GBIPPING FACE FOB CHU CKE AND METHOD Ol' KLRING THE BAIE Application med September 83, 1930. Serial No. 483,887.

This invention relates to improvements in chucks of the type commonly employed 1n connection with automa-tic screw machines for feeding and gripping the stock on which the machine is operating, and more particularly to the stock gripping faces of these chucks.

The objects of this invention are to iinprove the construction of stock engaging faces of chucks of this kind so as to materially improve their resistance to Wear; also to provide a rocess of making the gripping faces of chuc of this kind; also to improve the construction of and method of making the gripping faces of chucks of this kind in other respects hereinafter specified.

In the accompanying drawing:

Fig. 1 is a longitudinal view, partly in section, of a chuck having stock ripping pads provided with wear-resisting aces embodying this invention;

Fig. 2 is an end view thereof, partly in section, on line 2 2, Fig. 1; U

Fi 3 and 4 are face views of a gripping pad or a chuck, removed from the chuck, and showing different forms of stock gripping -faces' Fig. 5 is a sectional view of a ad, showing the same before the wear-resisting material is applied thereto;

Fig. 6 is a similar section showing the pad after the wear-resisting material has been ap lied; c

ig. 7 is a similar section after the gripping surface has been finished;

Fi 8 is a longitudinal section of a feed chuc of different construction havin work gripping faces embodying this invention applied thereto.

Two types of chucks are commonlyf 'em ployed in connection with screw machines, one chuck being provided with spring members formed to yieldingly grip the stock, this chuck being commonly referred to as a 45 feed finger. The other type of chuck has its spring members formed to normally disengage the stock, the members being pressed against the stock by suitable means for clamping the stock while the machine is work'- ing thereon, this type of chuck being coinmonlg called a collet. This invention is applica le to both types of chucks and to any other chucks having gripping faces which are subject to wear. The wear upon the gripping faces of feed fm ers is very great, since after each forward ceding movement, the gripping faces of the feed fingers, while' yieldingly pressed against the stock, are dragge along the face of the stock into position for the next feeding operation, and consequently, the life of the feed fingers or of the wearing pads, if such are used, isgenerally comparatively short. The collets, of course, are also subject to somewhat Vsimilar wear, and the replacing of either a feed finger or a collet in a screw machine necessitates the shutting down of the machine for a period of time sufiicient to permit the removing and replacing of the worn out part, and thus adds to the cost of producing the work, so that a material saving in this cost can be made by lengthening the life of the wearing faces of these chucks.

Figs. 1 to 7 illustrate the manner of applying my invention to a feed finger of a certain type aving removable wearing pads, and Fig. 8 shows the invention applied to a feed finger with integral wearing faces.

Referring to Figs. 1 and 2, A represents a chuck adapted to be laced in a machine, and the stock to be f (not shown) extends lengthwise through the interior of the chuck. The chuck is slotted as indicated at 10,

-thus forming betweenthe slots, spring members which normally act of their own resilience to engage the stock.

In the particular construction illustrated, a chuck is shown, which is intended to cooperate with stock gripping ads B, which are normally pressed toward t e stock by the 90 'The actionofthechuc thespringmemggnlgl of the chuck beinghx the construction illustrated, they would occupy when l ds in the construction vid at their outer surfaces with projections 12, which are adapted to enter into recesses 13 formedinthespringmembers 11 ofthe chuck for holding the pads in their operative itions. The chuck as well as the pads ma of any suitable or usual construction and of themselves do not constitute a part o this invention.

il?! order 1:0 increase tfhe lfich to mi' o e stoc engaging aces 4 o e portions of these surfaces of the pads are formed of suitable materials or alloys of an extremely hard nature. Materials of this kind are well known, and any desired material of this kind may be employed. Examples of such materials are tungsten carbide an a material known as Stellite.

In order to apply these materials to the stockengaging acesofthepads,thepads are first provided in their stock engagirci faces with or depressions into w i small quantities of these hard materials or alloys may be welded. For example in Figs. 2 and 3, depressions 16 and 17 are drilled into the'stock ging face of the pad. In Fig. 4, shallow, ongitudinal recesses 18 are cut into the stock engaging face 14 of the pad. It will be obvious that numerous other forms of depressions ma1 be employed in place of the two illustrate The portions of the pads of the chuck at and immediately adjacent to the depressions are then heated to a welding temperature by suitable means such as an Oxy-acetylene torch, by means of which the hard metallic substance is also welded into the or depressions inthestocke faces. Thisispreferably done by :u tportions of the hard metallic substance an droppin the fused substance into the depressions, w ereu it becomes welded to the metal of the pa If desired, the material may be fused and dropped into the depressions and welded to the pads by electrical means. The depreions thus act to retain the fused substance in the desired places in the stock faces. The pads will then have their filled as indicated at 19 in Fig. 6, and some of the excess material will extend above the level of the recesses; The pads are then subjected to a grinding operation in the usual manner to finish the stock engaging faces 14, and at the same time remove the excess of the hard material, thufs plloducin a smooth work engaging sur ace aving` spots or portions 20 therein, as illustrated in Fig. 7, the upper surfaces of which are flush with the other surfaces off the pads;e lnfs other may,o course, orfinishmg engaging faces of the pads.

The invention my nl in nppline4 u chu in which the 'p faces are fol-dig integral therewitglaslinmie construction illhustrahtedkFig. 8uicnk which C representstecuc ving Dortions 22 formed on the ends ortgmregilient members 24 thereof and spots or small surfns of the hnrdnnn mnrinl my be formed at intervals on these faces, as indicated at 25, the hard material being welded into or work engaging faces, and then the excess of hard material is und oil' as described in connection with t e pads B used in the constructionillustratedinFigslto'I.

The construction described has the advantage that the hardened portions of the stock engaging faces of the chucks will offer a very materially greater resistance to wear than other s'tlons of the chucks or pads, and will thus prevent the stock from wearing awa the softer rtions of the chucks or ince the h substances are confined 1n depressions or a: in the faces of the stock gripping arts, these substances are secoieyedconfn tlese racaaaaa s and are pr inst rea age or c 'ppi b -the metal :fthe chuck or ad. The plicessY and construction descri also has the advan that the hard wear-resisting material, w ich has a considerably higlher melting point than steel, is applied to t e stock engaging faces only at intervals so that only relatively small portions of the chucks or pads are heated to the high temperature necessary to effect welding of the hard alloys to the steel. This prevents the formation of excessive scale on the chucks or pads, and other damage which m' ht result if the entire stock enmg faces o the chucks or pads were ra' to the temperature necessary for welding the hard material thereto, such, for example, as distortion of the pads or chucks due to excessive heat.

While the drawing illustrates chucks adapted to o rate on stock of circular cross section, it w be obvious that this invention is equally applicable to chucks or pads for use 1n connection with stock of other cross section.

I claim as my invention:

1. A chuck having a stock engaging face provided with wear-resisting portions in which a shallow recess is formed in said face, and an insert of a hard, brittle metallic material having relatively low tensile strength welded in said recess to the metal of said chuck, with the metal of the chuck forming a reinforcement on all sides except the face of the insert. v

2. A chuck having a stock engaging face provided at intervals in said face with wearresisting portions, said stock engaging face being provided with recesses formed at intervals in said face, and having inserts of a hard, brittle metallic substance of low tenllt sle strength welded in said recesses to the metal of said chuck, with the metal of said chuck forming a reinforcement on all sides of each of the several inserts except the faces 5. of the inserts.

3. A chuck having spring members, stock engaging pads secured to said spring members and having stock engaging faces provided with wear resisting portions, said pads l0 having shallow recesses formed in said faces,

/' and inserts of a hard, brittle metallic material of low tensile strength welded in said recesses to the metal of said pads, the metal f of the ads forming a reinforcement on all s l5" sides o said inserts except the faces thereof.

LEIGH n. EVANS. 

